1. Field of the Invention
The present invention relates to a pesticide with a physical mode of action, containing a low concentration of active ingredient, for use on agricultural plants and soils, which is safer for the environment and humans than traditional pesticides.
2. Description of the Related Art
Insect and fungus induced spoilage of agricultural commodities, such as fruits and vegetables, has been estimated to result in losses of approximately 30% of crops in the United States and up to 50% of crops worldwide.
Agricultural crop losses are primarily caused by insect pest damage and plant diseases. Examples of major crop pests include whiteflies (e.g. Bemesia tabaci), mites, aphids and caterpillars that damage crops through direct feeding in fruit and foliage. Insects may also act as vectors of bacterial or viral plant diseases where controlling the insect vector is the only means of preventing infection. Thus, effective agricultural practices to control insect pests and diseases are essential to prevent excessive crop losses.
Conventional agricultural chemical pesticides to control insects and funguses are commonly formulated as solid compositions such as water-dispersible, granular compositions and wettable powder compositions. Conventional solid compositions comprise an active compound, a mineral carrier, and a wetting agent and/or a dispersing agent (see e.g., U.S. Pat. No. 6,093,682; U.S. Pat. No. 5,595,749; U.S. Pat. No. 4,804,399). Pesticide active ingredients are also delivered in solid carriers such as kaolin, chalk, limestone, sodium and potassium alumina silicates, corn meals, sawdust, cellulose powder, activated charcoal and the like. However, such compositions often leave toxic residues which may have an extended impact on humans and the environment.
Hydrocolloids have been used as a delivery system for conventional pesticide active ingredients and are well known in the art. For example, Rascher et al. in U.S. Pat. No. 5,595,749, describes an organophosphate ester active ingredient delivered in a hydrocolloid agent and silicate complex.
Strains of chemical pesticide tolerant insects are increasing at alarming rates, rendering chemical treatments less effective or totally ineffective for agricultural purposes. For this reason, multiple active ingredients are sometimes used simultaneously to improve control of pesticide resistant pest populations. However, this practice often results in a similar decrease in the effectiveness as resistance can also develop rapidly in the pest population against multiple active ingredient pesticides.
Other problems with the use of chemical pesticides are many, including acute and chronic mammalian toxicity, carcinogenicity and other effects on humans and animals that come into contact with them. Moreover, humans who consume produce treated with conventional pesticides and those who are exposed to the environmental conditions they leave behind are at risk. At a time when conventional pesticide use is being restricted and/or eliminated, there is clearly an urgent need to develop new methods of controlling pests, including insects and funguses, that destroy agricultural commodities, which are safer to humans, environmentally benign and effective.
In response to this need, pesticides directed to a physical mode of action rather than a chemical kill have been pursued. However, prior physical kill pesticides have been used with mixed success. Their use of ingredients in high concentrations leads to various problems such as clogging of spray equipment, uneven and problematic application and reduced efficiency of application machinery. Signifigantly, the use of existing physical kill pesticides has also been associated with crop damage from the high concentrations of the physical control active ingredients used in these compositions.
Accordingly, there is a need in the art for a pesticide to effectively control insects and funguses that cause loss of agricultural commodities, such as fruits, vegetables, fiber and flowers. There is a further need for pesticides that are safer for workers, consumers and the environment and can be delivered efficiently and effectively in an aqueous form.